<body>
  All of the classes that support the context schema are in this
  package. The context schema contains the request and response formats,
  and so there are classes to handle everything that goes into these
  exchange formats. All of the classes in this package, and all the
  related classes used by this package are parsable and encodable, so
  it's easy to build a PEP and a PDP using these routines.
</body>
